The present invention relates to the field of foundation and soil irrigation and more specifically to a irrigation system having multiple independent zones for optimizing the moisture saturation of soil around the foundation of a structure.
The expansion and contraction of soil is a significant factor in causing damage to the foundations of buildings and other structures. Such expansion and contraction results from changes in the moisture content of the soil and is particularly evident in clay soil. The changes in volume of the soil can place undesirable forces upon a foundation so as to cause structural damage.
Moisture content of soil can change for a variety of reasons. For example, water can be removed from the soil by the processes of transpiration via the presence of vegetation, evaporation and gravity. Such processes can create areas of localized water depletion as well as larger area wet/dry cycles that can cause a foundation to sag, crack and move, eventually leading to structural failure.
Attempts have been made in the prior art to stabilize the moisture content of soil around foundations:
U.S. Pat. No. 4,534,143 to Goines et al. discloses a soil moisture stabilization system comprising two circumferential zones around a house, where one circumferential zone is placed approximately three feet below the other.
U.S. Pat. No. 4,878,781 to Gregory et al. discloses a moisture control system comprising a plurality of supply pipes, accumulator pipes, and porous pipes for supplying water, storing water and allowing water to seep into surrounding soil.
U.S. Pat. No. 5,156,494 to Owens et al. discloses a soil moisture stabilization system that operates based on stress sensors placed on the foundation. Water is injected into the soil around a foundation when the stress sensors detect abnormal amounts of stress.
Despite these efforts, there remains a need for the development of an effective foundation and soil irrigation system. There is a particular need for a system that can optimize soil saturation and control specific sections around a structure that may need differing levels of moisture to achieve saturation.
The present invention provides a method and apparatus for a foundation and soil irrigation system having multiple independent zones that can be controlled to deliver water or other fluid through a fluid distribution network to surrounding soil (hereinafter, water will be generically used to represent any type of fluid suitable for transportation and distribution to soil). The system can be installed above or below ground, but in a preferred embodiment the system is subterranean and is installed 18 to 24 inches off of the foundation and 12 to 18 inches below ground level. Each independent zone comprises a network of sections that are connected together in predetermined increments to ensure proper hydraulic flow throughout the zone.
Optimum moisture saturation is achieved through the control of moisture content and user intervention. A controller enables each zone to water independently of the others. When a zone is selected to be turned xe2x80x9conxe2x80x9d, the controller is set to deliver water to the zone. Water is then distributed to the surrounding soil until the zone is turned xe2x80x9coffxe2x80x9d and water ceases to flow within the zone. Hydraulics and flow are balanced to achieve accurate saturation.
It is therefore one aspect of the invention to provide a foundation irrigation system comprising at least two independent zones, wherein each zone comprises a water distribution network that forms at least one center-fed or end-fed section of predetermined length. Such a predetermined length could optimally be in the range of 5 to 20 feet. A controller governs the flow of water to the independent zones. The water distribution network comprises a water transportation system and a soil moisturization system.
It is another aspect of the invention to provide a method of foundation irrigation comprising installing at least two independent zones around a foundation, feeding at least one section in each of the independent zones, and controlling the flow of water to said zones so as to allow each zone to water independently of other zones. Feeding the independent zones can be done by center-feeding, feeding at one-end, both ends, or any combination thereof. Optimal moisture saturation can be achieved through the manual monitoring of moisture content and user intervention.